Intramolecular Cyclopropanation: Stereospecific Synthesis of (E)- and (Z)-1-Aminocyclopropane-1-carboxylic Acids
tert-Butyl-substituted allyl malonates, prepared in two steps from malonic acid, are diazotized in high yields.The diazomalonates 7 undergo a stereospecific copper(I)-catalyzed cyclopropanation to give 1-(tert-butoxycarbonyl)-3-oxa-2-oxobicyclohexanes 8 which can be converted to the protected (E)- or (Z)-1-aminocyclopropane-1-carboxylic acids 10 or 15 via Curtius- or Hoffmann-type rearrangements, respectively.The sequences are short (six steps from malonic acid) and proceed with good overall yields (20-40percent overall from malonic acid).The free amino acids 12 and 13 can be liberated in two steps.
Koskinen, Ari M. P.,Munoz, Luis
p. 879 - 886
(2007/10/02)
Hetero-Substituted Methylideneoxazolones. 2,3-Methanohomoserine and -methionine Synthesis
The use of hetero-substituted methylideneoxazolones 2-4 in the synthesis of 1-aminocyclopropanecarboxylic acid derivatives is described.The serendipitous formation of bromomethyl spirooxazolones 11 afforded a simple method for the synthesis of both 2,3-me
Bland, J.,Shah, A.,Bortolussi, A.,Stammer, C. H.
p. 992 - 995
(2007/10/02)
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